The invention relates to a read head for acquiring digital images of postal objects in a postal sorting installation, said read head including a high-resolution camera providing a multiple level gray scale. The invention is more particularly designed for a postal sorting installation in which postal objects are processed by video coding so that an operator inputs the destination address on the basis of the digital image of the object that is displayed on a screen on the video-coding station of the operator. The digital images are generally transmitted in real time from a computerized management system of the sorting installation to the video-coding station via a computer network. In view of the processing throughput, the digital images must be small in size otherwise it is not possible to video code the postal objects in real time.
Generally, the size of the images is restricted by limiting their resolution and/or their palette of colors. Conventionally, the images acquired are high-resolution gray scale images because the size of high-resolution color images is not compatible with transfer rates over current computer networks. The images displayed on the screen of the video-coding station are currently gray scale images, which reduces the effectiveness of the operator and the comfort conditions under which the operator works.
Document U.S. Pat. No. 5,912,698 discloses a read head for acquiring digital images of postal objects in a postal sorting machine. That read head comprises a high-resolution gray scale camera and a low-resolution color camera. The two cameras are disposed in the read head so as to provide two separately acquired and superposable digital images of each postal item.